The elevator car of elevators is most generally moved with hoisting roping, which comprises one or more ropes. To ensure safety and availability, the hoisting roping must be kept in good condition. The hoisting roping is most generally fixed at its ends to the building and/or to the elevator car and to the counterweight, depending on the suspension ratio and otherwise on the type of roping. In connection with the operation of the elevator, the hoisting roping with its rope(s) moves as the elevator car moves. The speed of movement of the elevator car and of the hoisting ropes is most generally controlled with a traction sheave, and the hoisting ropes are also guided to pass along the desired route by means of diverting pulleys. Wear is caused in the hoisting ropes over time owing to, among other things, fatigue produced by their guidance and by traction sheave contact as well as by repeated bending and tensile stress.
The ropes of the suspension roping of elevators, including the overspeed governor ropes of the elevator, have conventionally been manufactured from metal. Known in the art are also elevators in which is used hoisting roping comprising ropes that have load-bearing composite parts. This type of solution is presented in e.g. publication WO 2009090299. The overspeed governor ropes of an elevator are helical ropes of round cross-sectional shape, the force-transmitting parts of which ropes are of metal material. A problem in solutions according to prior-art is that the strength properties of metal in relation to its mass are such that the mass of the rope increases to be large. When producing acceleration or deceleration in the elevator car, a corresponding change in speed must also be produced in the overspeed governor rope. The magnitude of the energy consumed for this depends on the mass of the rope. Yet another problem has been the creeping of metal ropes.
It is known in the art that the condition of prior-art ropes of an elevator can be assessed visually. One problem, among others, is that it has been necessary to assess the condition of all the ropes of an elevator separately. Problems have also been caused by the fact that it has been awkward to visually observe the condition of coated ropes of an elevator.
Efforts have been made to solve the problem of condition monitoring in connection with composite-structured elevator ropes according to prior art with a method wherein one of the load-bearing parts of the rope is arranged to be more susceptible to breakage in relation to the number of bends than the other load-bearing parts, and in the method the condition of the load-bearing part that is most susceptible to breakage is monitored.
There have, however, been problems with the reliability of the method and it has not been possible with the method to obtain quantitive data about the wear of an elevator rope.